Not applicable.
1. Field of the Invention
The present invention relates generally to a disk drive having a head stack assembly having a tang which impacts a latch, and more particularly to a damping member disposed between the latch and the tang with the head stack assembly in a parked position.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA). The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base. The hub has an outer hub flange that supports a lowermost one of the disks. Additional disks may be stacked and separated with annular disk spacers that are disposed about the hub. The head stack assembly has an actuator assembly having at least one transducer head, typically several, for reading and writing data to and from the disk. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached heads are moved relative to tracks disposed upon the disk.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit cable assembly. A conventional xe2x80x9crotaryxe2x80x9d or xe2x80x9cswing-typexe2x80x9d actuator assembly typically comprises an actuator body that rotates on a pivot assembly between limited positions, a coil portion that extends from one side of the actuator body to interact with one or more permanent magnets to form a voice coil motor, and one or more actuator arms which that extend from an opposite side of the actuator body. A head gimbal assembly includes at least one transducer head, sometimes two, which is distally attached to each of the actuator arms. The actuator assembly includes the actuator body that has a bore and a pivot bearing cartridge engaged within the bore. The at least one head gimbal assembly and the flex circuit cable assembly are attached to the actuator assembly.
Each magnetic disk includes opposing disk surfaces. Data may be recorded on a single surface or both along data annular regions. Non-data annular regions are typically disposed at the interior-most portion of the disk drive surfaces (typically referred to landing or parking zones). The non-data annular regions do not include any recorded data. When the disk drive is deactivated, the heads are xe2x80x9cparkedxe2x80x9d at a position where they will not damage portions of the disk surface containing recorded data. As such, the head stack assembly may be pivoted such that each transducer head is disposed adjacent the non-data annular region. The head stack assembly further includes a tang that extends from the coil portion. The head stack assembly is configured to rotate to a parked position with the tang impacting a latch. The latch is attached to the disk drive base. The latch may include a magnet element that magnetically attracts the tang for latching the head stack assembly to the latch in the parked position.
A topic of concern is the desire to reduce the effects of the impact between the tang and the latch when moving the head stack assembly to the parked position. Accordingly, there is a need in the art for an improved head stack assembly latching arrangement in comparison to the prior art.
An aspect of the invention can be regarded as a disk drive that includes a disk drive base. The disk drive further includes a latch attached to the disk drive base. The latch includes a latch impact surface having a latch impact surface perimeter. The latch impact surface perimeter defines a latch impact surface area. The disk drive further includes a head stack assembly coupled to the disk drive base. The head stack assembly includes a coil portion and a tang extending from the coil portion. The head stack assembly being sized and configured to rotate to a parked position with the tang in mechanical communication with the latch. The tang has a tang impact surface. The disk drive further includes a damping member disposed upon the latch adjacent the latch impact surface and disposed between the latch and the tang with the head stack assembly in the parked position for damping impact between the tang and the latch and mitigating contact between the tang impact surface and the latch impact surface. The damping member has a damping member perimeter defining a damping member surface area less than the latch impact surface area.
According to an embodiment of the present invention, the latch includes a latch cup and a latch cap disposed within the latch cup. The latch cup has a cup open end. The cup open end defines the latch impact surface perimeter. The cap closed end defines a cap closed end surface area. The damping member surface area is less than the cap closed end surface area. The cap closed end is off-set from the cup open end away from the tang by an off-set depth. The damping member has a damping member thickness greater than the off-set depth. The latch includes a magnetic element for magnetically attaching the tang to the latch with the head stack assembly in the parked position. The magnetic element is disposed within the latch cap. The damping member is generally circular and planar. The damping member is adhesively attached to the latch. The damping member includes a damping member contact surface for contacting the tang impact surface and a damping member attachment surface for attaching the damping member to the latch. The damping member is formed of a viscoelastic adhesive. The damping member is deformable with the damping member contact surface moving relative to the damping member attachment surface upon contact between the tang impact surface and the damping member contact surface.
According to another aspect of the present invention, there is provided a disk drive that includes a disk drive base. The disk drive further includes a latch attached to the disk drive base. The latch includes a latch impact surface. The disk drive further includes a head stack assembly coupled to the disk drive base. The head stack assembly includes a coil portion and a tang extending from the coil portion. The head stack assembly is sized and configured to rotate to a parked position with the tang in mechanical communication with the latch. The tang has a tang impact surface. The disk drive further includes a damping member disposed upon the latch adjacent the latch impact surface and disposed between the latch and the tang with the head stack assembly in the parked position for damping impact between the tang and the latch and mitigating contact between the tang impact surface and the latch impact surface. The damping member has a damping member contact surface for contacting the tang impact surface and a damping member attachment surface for attaching the damping member to the latch. The damping member is deformable with the damping member contact surface moving relative to the damping member attachment surface upon contact between the tang impact surface and the damping member contact surface.
According to an embodiment of the present invention, the latch impact surface has a latch impact surface perimeter. The latch impact surface perimeter defines a latch impact surface area. The damping member has a damping member perimeter that defines a damping member surface area less than the latch impact surface area. The latch may include a latch cup and a latch cap disposed within the latch cup. The latch cup has a cup open end. The cup open end defines the latch impact surface perimeter. The latch cap has a cap closed end that defines a cap closed end surface area. The damping member surface area is less than the cap closed end surface area. The cap closed end is off-set from the cup open end away from the tang by an off-set depth. The damping member has a damping member thickness greater than the off-set depth. The latch includes a magnetic element for magnetically attaching the tang to the latch with the head stack assembly in the parked position. The magnetic element is disposed within the latch cap. The damping member is generally circular and planar. The damping member is adhesively attached to the latch. The damping member is formed of a viscoelastic adhesive.